I have an SD card that is always in my 1000h. Whenever I would resume from sleep I would receive an error that the card was not correctly unmounted. Heres an article I found that will fix this problem.

If you followed every step from the install wiki, then you would have already installed Sleepwatcher. After you type 'sudo visudo' in the terminal, and add the correct line, you have to press 'Esc' and then type 'w:' (without the apostrophes) then press enter to save your changes. It doesn't tell you that in the guide, and just closing the terminal window will not save your changes.

Also if you just want to unmount a normal drive, not a backup drive linked to time machine, you would change the line:
sudo /sbin/umount -f /Volumes/Phil\ Backup
to
sudo /sbin/umount -f /Volumes/Phil
You would obviously change the word Phil to name of your external drive. If the name of your drive has a space in it, then you have to add quotation marks around the name of your drive. So if your drive was called 'SD Card' then it would look like this:
sudo /sbin/umount -f /Volumes/"SD Card"

Now my sd card unmounts correctly when I put it to sleep. Hope this helps someone.